Micro-aluminum powder with bi- or tri-component alloy coating as a promising catalyst: Boosting pyrolysis and combustion of ammonium perchlorate

A novel design of micro-aluminum (μAl) powder coated with bi-/tri-component alloy layer, such as: Ni–P and Ni–P–Cu (namely, Al@Ni–P, Al@Ni–P–Cu, respectively), as combustion catalysts, were introduced to release its huge energy inside Al-core and promote rapid pyrolysis of ammonium perchlorate (AP) at a lower temperature in aluminized propellants. The microstructure of Al@Ni–P–Cu demonstrates that a three-layer Ni–P–Cu shell, with the thickness of ∼100 nm, is uniformly supported by μAl carrier (fuel unit), which has an amorphous surface with a thickness of ∼2.3 nm (catalytic unit). The peak temperature of AP with the addition of Al@Ni–P–Cu (3.5%) could significantly drop to 316.2 °C at high-temperature thermal decomposition, reduced by 124.3 °C, in comparison to that of pure AP with 440.5 °C. It illustrated that the introduction of Al@Ni–P–Cu could weaken or even eliminate the obstacle of AP pyrolysis due to its reduction of activation energy with 118.28 kJ/mol. The laser ignition results showed that the ignition delay time of Al@Ni–P–Cu/AP mixture with 78 ms in air is shorter than that of Al@Ni–P/AP (118 ms), decreased by 33.90%. Those astonishing breakthroughs were attributed to the synergistic effects of adequate active sites on amorphous surface and oxidation exothermic reactions (7597.7 J/g) of Al@Ni–P–Cu, resulting in accelerated mass and/or heat transfer rate to catalyze AP pyrolysis and combustion. Moreover, it is believed to provide an alternative Al-based combustion catalyst for propellant designer, to promote the development the propellants toward a higher energy

Progress of Jinping Underground laboratory for Nuclear Astrophysics (JUNA)

Jinping Underground lab for Nuclear Astrophysics (JUNA) will take the advantage of the ultralow background in Jinping underground lab, high current accelerator based on an ECR source and highly sensitive detector to study directly a number of crucial reactions to the hydrostatic stellar evolution for the first time at their relevant stellar energies. In its first phase, JUNA aims at the direct measurements of 25Mg(p,γ)26Al, 19F(p,α)16O, 13C(α,n)16O and 12C(α,γ)16O. The experimental setup, which include the accelerator system with high stability and high intensity, the detector system, and the shielding material with low background, will be established during the above research. The current progress of JUNA will be given

Progress of Jinping Underground laboratory for Nuclear Astrophysics (JUNA)

Jinping Underground lab for Nuclear Astrophysics (JUNA) will take the advantage of the ultralow background in Jinping underground lab, high current accelerator based on an ECR source and highly sensitive detector to study directly a number of crucial reactions to the hydrostatic stellar evolution for the first time at their relevant stellar energies. In its first phase, JUNA aims at the direct measurements of 25Mg(p,γ)26Al, 19F(p,α)16O, 13C(α,n)16O and 12C(α,γ)16O. The experimental setup, which include the accelerator system with high stability and high intensity, the detector system, and the shielding material with low background, will be established during the above research. The current progress of JUNA will be given

Commissioning of Underground Nuclear Astrophysics Experiment JUNA in China

Underground Nuclear Astrophysics Experiment in China (JUNA) has been commissioned by taking the advantage of the ultra-low background in Jinping underground lab. High current mA level 400 KV accelerator with an ECR source and BGO detectors were commissioned. JUNA studies directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. In the first quarter of 2021, JUNA performed the direct measurements of 25Mg(p,γ)26Al, 19F(p,α)16O, 13C(α,n)16O and 12C(α,γ)16O near the Gamow window. The experimental results reflect the potential of JUNA with higher statistics, precision and sensitivity of the data. The preliminary results of JUNA experiment and future plan are given